Advanced diffusion imaging of periventricular nodular heterotopia in 2 drug-resistant epilepsy patients
Abstract number :
1.166
Submission category :
5. Neuro Imaging
Year :
2015
Submission ID :
2320698
Source :
www.aesnet.org
Presentation date :
12/5/2015 12:00:00 AM
Published date :
Nov 13, 2015, 12:43 PM
Authors :
Lohith Kini, Carlos Coto, Joel M. Stein, Kathryn Davis
Rationale: Approximately 1/3 of patients with neocortical localization related epilepsy have clinical MRIs that no not identify a lesion (Tellez-Zenteno et al Epilepsy Res. 2010 May; 89(2-3):310-8). Identification of subtle malformations of cortical development that are missed by traditional epilepsy imaging sequences is important for appropriate clinical management and selection of therapy. Advanced diffusion imaging sequences produces maps of neurite density and dispersion that are altered in epileptogenic lesions, and could be helpful in identifying subtle lesions.Methods: Patients were imaged on a Siemens Trio Magnetom 3T scanner using a 32-channel phased-array head coil as well as a research Siemens 7T scanner (Siemens Healthcare, Erlangen, Germany). Images collected include T1-weighted MP-RAGE, high-resolution T2 weighted imaging and an additional NODDI protocol optimized for a 3T Siemens Magnetom scanner. The NODDI protocol consisted of three DWI acquisitions using a twice refocusing spin-echo with EPI readout. The acquisition parameters were single-shot EPI, 2.5 mm × 2.5 mm axial slices, 96 × 96 matrix, field-of-view 24 cm × 24 cm, TE 97 ms, TR 7000 ms, 16 non-diffusion weighted acquisitions (b=0), 8 directions with b-value 300 s/mm2, 31 directions with b-value 700 s/ mm2, 64 directions with b-value 2000 s/ mm2. Constant scan parameters were TR/TE = 5216 ms/100 ms, parallel imaging factor 2, 50 slices, voxel size 2.5 x 2.5 x 2.5 mm3. Anatomical images were acquired for cortex parcellation with a T1-weighted MPRAGE (TR/TE = 1810 ms/3.51 ms, 160 slices, 1.00 mm thickness) and T2-weighted (TR/TE=3200 ms/375 ms, 192 slices, 0.73 mm thickness). All images were processed using ITK-SNAP (Yushkevich et al Neuroimage 2006 Jul 1;31(3):1116-28). Lesions were manually segmented by an expert neuroradiologist (J.M.S.).Results: We report 2 cases of a 19-year old woman and a 20-year old woman referred to our center for severe epilepsy despite aggressive treatment with anti-epileptic medications. DTI imaging and neurite density mapping showed decreased fractional anisotropy, decreased mean and radial diffusivity, increased neurite dispersion and density in lesions that were suggestive of periventricular nodular heterotopias (Figure 2). Both patients underwent Vagal Nerve Stimulators (VNS) due to presence of these malformations.Conclusions: Advanced diffusion image sequences may be helpful in identifying periventricular nodular heterotopias in patients with drug-resistant epilepsy, and could be performed in future neuroimaging explorations. (Funding Sources: P20 NS12006 (NIH NINDS))
Neuroimaging